Browsing by Author "Convertino, Victor A"
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- ItemCardiovascular consequences of weightlessness promote advances in clinical and trauma care.(2005-08-16) Cooke, William H; Convertino, Victor ACardiovascular adaptations driven by exposure to weightlessness cause some astronauts to experience orthostatic intolerance upon return to Earth Maladaptations of spaceflight that lead to hemodynamic instability are temporary and therefore astronauts provide for researchers a powerful model to study cardiovascular dysfunction in terrestrial patients Orthostatic intolerance in astronauts is linked to changes in the autonomic control of cardiovascular function and so patients that suffer neurocardiogenic syncope may benefit from a greater understanding of the effects of spaceflight on the autonomic nervous system In addition appropriate autonomic compensation is fundamental to the maintenance of stable arterial pressures and brain blood flow in patients suffering traumatic bleeding injuries The application of lower body negative pressure LBNP an experimental procedure used widely in aerospace physiology induces autonomic and hemodynamic responses that are similar to actual hemorrhage and therefore may emerge as a useful experimental tool to simulate hemorrhage in humans Observations that standing astronauts and severely injured patients are challenged to maintain venous return has contributed to the development of an inspiratory impedance threshold device that serves as a controlled Mueller maneuver and has the potential to reduce orthostatic intolerance in returning astronauts and slow the progression to hemorrhagic shock in bleeding patients In this review we focus on describing new concepts that have arisen from studies of astronauts patients and victims of trauma and highlight the necessity of developing the capability of monitoring medical information continuously and remotely Remote medical monitoring will be essential for long duration space missions and has the potential to save lives on the battlefield and in the civilian sector
- ItemHeart period variability in trauma patients may predict mortality and allow remote triage.(2006-11-07) Cooke, William H; Salinas, José; McManus, John G; Ryan, Kathy L; Rickards, Caroline A; Holcomb, John B; Convertino, Victor AThe high frequency to low frequency ratio HF LF derived from analysis of heart period variability is elevated and associated with mortality in severely injured patients monitored in a hospital The purpose of this study was to test the utility of heart period variability measurements as indicators of injury severity in patients prior to definitive medical intervention We tested the hypothesis that survival is associated with low relative HF LF and death is associated with high relative HF LF
- ItemIdentifying physiological measurements for medical monitoring: implications for autonomous health care in austere environments.(2008-03-31) Convertino, Victor A; Ryan, Kathy LIn a patient who has lost a significant amount of blood avoiding cardiovascular collapse and impending circulatory shock depends on the ability to maintain adequate arterial blood pressure in the presence of significant central hypovolemia Our analysis of hemodynamic autonomic and metabolic data obtained from healthy human subjects exposed to progressive reduction in central blood volume and supported by data from trauma patients provide evidence to support the following conclusions 1 Because of autonomically mediated compensatory mechanisms standard vital signs can remain unchanged or change too late when cardiovascular collapse is imminent 2 Currently proposed closed loop resuscitation and oxygen delivery systems controlled by arterial blood pressure and SpO2 may prove inadequate for early intervention decision support 3 Continuous capture of PP ECG R wave amplitude indices of HRV cardiac BRS and or muscle PO2 could improve the sensitivity of closed loop resuscitation and oxygen delivery by providing earlier indications of clinical status
- ItemIs heart rate variability better than routine vital signs for prehospital identification of major hemorrhage?(2014-12-23) Edla, Shwetha; Reisner, Andrew T; Liu, Jianbo; Convertino, Victor A; Carter, Robert; Reifman, JaquesDuring initial assessment of trauma patients metrics of heart rate variability HRV have been associated with high risk clinical conditions Yet despite numerous studies the potential of HRV to improve clinical outcomes remains unclear Our objective was to evaluate whether HRV metrics provide additional diagnostic information beyond routine vital signs for making a specific clinical assessment identification of hemorrhaging patients who receive packed red blood cell PRBC transfusion